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What is CDA?

Clinical Document Architecture (HL7 CDA R2) is an XML-based document standard for clinical documents — discharge summaries, referrals, operative notes, and patient summaries. It separates a human-readable narrative from machine-readable structured entries.

CDA is still widely deployed in Slovak and EU eHealth systems, particularly for patient summaries sent via NCZI infrastructure. EHDS is migrating these to FHIR-based formats.

CDA document header (abbreviated)

<ClinicalDocument xmlns="urn:hl7-org:v3">
  <typeId root="2.16.840.1.113883.1.3" extension="POCD_HD000040"/>
  <id root="2.16.840.1.113883.19.4" extension="c266"/>
  <code code="34133-9" codeSystem="2.16.840.1.113883.6.1"
        displayName="Summary of episode note"/>
  <title>Patient Summary</title>
  <effectiveTime value="20240315120000"/>
  <recordTarget>
    <patientRole>
      <id root="2.16.840.1.113883.2.9.4.3.2" extension="987654321"/>
      <patient>
        <name><given>Jana</given><family>Horváth</family></name>
        <administrativeGenderCode code="F"/>
        <birthTime value="19850315"/>
      </patient>
    </patientRole>
  </recordTarget>
</ClinicalDocument>

CDA structure

Header: document metadata — id, type, date, author, patient, custodian
Body — narrative (level 1): human-readable text in <section><text> — sufficient for legal validity
Body — coded entries (level 3): machine-readable <entry> elements with SNOMED/LOINC codes — required for interoperability